public async Task <IActionResult> Login(LoginModel credentials)
        {
            var result = await _signInManager.PasswordSignInAsync(credentials.Username, credentials.Password, false, false);

            if (result.Succeeded)
            {
                var user = await _userManager.FindByNameAsync(credentials.Username);

                string token = _tokenBuilder.Create()
                               .WithClaim(new Claim("id", user.Id))
                               .WithClaim(new Claim("username", user.UserName))
                               .Build();


                var output = new LoginOutputModel()
                {
                    Id = user.Id, Username = user.UserName, Token = token
                };

                return(Ok(output));
            }

            return(Unauthorized());
        }